JPH10159841A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing with electric erosion and creep preventing ability, which is effectively used as a free side bearing to allow movement is axial direction between a journal box and a shaft. SOLUTION: Plural circumferential grooves 11 are provided in the outer diameter face of an outer wheel 2 and an insulating coat 8 formed of an electrically insulating resin or synthetic rubber is provided on the outer diameter face of the outer wheel. Electically insulating elastic rings 10 such as O-rings are mounted on the circumferential grooves 11 in a demountable manner. When a bearing is mounted on a journal box 15, grease or other oil is applied to parts between the circumferential grooves 11, 11 in the outer diameter face of the outer wheel. If creep prevention is not required, the outer wheel 2 is mounted in the journal box 15 in the state that the elastic rings 10 are demounted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor used in a place where electrolytic corrosion is a problem, such as an inverter motor or a motor installed near the inverter motor, and at the same time, in a place where outer ring creep is likely to be a problem. The present invention relates to a rolling bearing used, particularly a rolling bearing suitable for a free-side bearing that allows axial movement due to thermal expansion of a shaft or the like, and a mounting structure thereof.

[0002]

2. Description of the Related Art At present, sealed deep groove ball bearings are usually used as motor bearings. However, recently, the number of inverter control motors has been increasing, and with this increase, the problem of electrolytic corrosion between the rolling elements and the inner ring or the outer ring has been increasing. Further, in this type of motor, there is a case where a problem of wear of the inner diameter surface of the axle box is caused due to the outer ring creep phenomenon. As a countermeasure against the electrolytic corrosion, various types in which an insulating coating made of resin or rubber is provided on the outer ring have been proposed and put into practical use. As shown in FIG. 5, a bearing for preventing creep is formed with a circumferential groove at two locations on the outer diameter surface of an outer ring 51, and an O-ring 52 is attached thereto. 54 has been proposed. In the assembled state, the oil 53 is held between the pair of O-rings 52, the outer diameter surface of the outer ring, and the inner diameter surface of the axle box, so that the creep force is reduced, and the friction coefficient of the O-rings 52 prevents creep. Is done.

[0003]

However, the anti-creep bearing of FIG. 5 does not have the function of preventing electrolytic corrosion, and the bearing provided with the insulating coating does not have the function of preventing creep. As described above, although there are bearings having the sole functions of preventing corrosion and creep, there is no suitable bearing having both functions.

As a bearing having both functions of preventing electrolytic corrosion and preventing creep, as shown in FIG. 6, the present applicant has provided an insulating coating 62 on the outer diameter surface and width surface of an outer ring 61, and the insulating coating 62. (Japanese Patent Application No. Hei 6-23170) is proposed in which a ring-shaped expansion correction layer 63 made of a resin having a larger linear expansion coefficient than that of the insulating coating is provided on the outer diameter surface.
issue). However, in this case, the creep prevention can be prevented by fitting the outer ring 61 to the axle box as the temperature rises when the axle box is made of a material such as aluminum which has a larger linear expansion coefficient than the outer ring 61 of the bearing. The purpose of the present invention is to prevent the occurrence of creep at a high temperature, and to prevent creep by the large linear expansion coefficient of the expansion compensation layer 63 especially at high temperatures. Therefore, the general creep prevention function cannot be said to be sufficient. The expansion compensation layer 63 has a flat outer surface so as to be in close contact with the axle box in order to reliably prevent creep, but this also prevents the axial movement between the outer ring 61 and the axle box. You. Therefore, the bearing shown in FIG. 6 is not suitable for use as a free-side bearing that allows axial movement due to thermal expansion of the shaft.

On the other hand, depending on the location where the bearing is used, the creep preventing function may not be required, and only the electrolytic corrosion preventing function may be required. In such a case, as shown in FIG. If the bearings protrude, the expansion compensation layer 63 may hinder the insertion of the bearing into the axle box, and may rather hinder the expansion compensation layer 63. Therefore, it is difficult for one bearing to cope with a part that requires the creep preventing function and the electrolytic corrosion preventing function and a part that requires only the electrolytic corrosion preventing function.

The present invention has been made to solve the above-mentioned problems, and can prevent both electrolytic corrosion and creep, and is also effective for use as a free-side bearing which allows axial movement between an axle box and a shaft. An object is to provide a rolling bearing. Another object of the present invention is to provide a portion where the anti-creep function and the anti-corrosion function are required and a portion where only the anti-corrosion function is required,
The purpose is to be able to cope with one bearing without lowering the mountability.

[0007]

A rolling bearing according to the present invention is characterized in that a plurality of circumferential grooves are provided on an outer diameter surface of an outer ring, and an insulating coating having electrical insulation is provided on an outer diameter surface of the outer ring. An electrically insulating elastic ring having an outer diameter protruding from the insulating coating is attached to the groove. According to this configuration, when the elastic ring is pressed into the shaft box, a creep preventing function can be obtained by the frictional force. In addition, since the entire outer diameter surface of the outer ring is covered with an electrically insulating insulating coating and an elastic ring, electric corrosion between the rolling element and the inner ring or the outer ring due to a potential difference between the axle box and the shaft is prevented. You. When the bearing is mounted on the axle box, it is desirable to apply oil to a portion between the two elastic rings on the outer diameter surface of the outer ring. By applying the oil in this manner, the oil is held between the insulating coating and the elastic rings on both sides and the inner diameter surface of the axle box, so that the frictional force serving as a creep force is reduced, and the frictional force of the elastic ring is reduced. In combination with this, an excellent creep preventing action can be obtained. As described above, since the creep preventing effect is enhanced by the oil in the sealed state, the resistance of the outer ring to the axial box in the axial direction is small, and the oil can be used as a free-side bearing.

In the above structure, the insulating coating is provided over the width surface of the outer race and the inner surface of the circumferential groove, and an electric wire having an outer diameter protruding from the insulating coating in the circumferential groove provided with the insulating coating. An insulating elastic ring may be detachably attached. By providing the insulating coating up to the width of the outer ring as in this configuration, the effect of preventing electrolytic corrosion is enhanced. Also,
When the elastic ring is detachable as described above, it can be used as a bearing having an insulating function and an outer ring creep prevention function by using the elastic ring in the attached state, and if the elastic ring is removed and used, only the insulating function can be used. It can be used as a bearing having Depending on the place of use, the anti-creep function may not be required.By making the elastic ring detachable in this way, the same bearing can be used for different purposes and compared to the case where different bearings are manufactured. It is easy to mass-produce and manage, and can be produced at low cost. Also, if you do not need anti-creep function,
By removing the elastic ring, the mountability to the axle box is improved. Also in the case of the bearing having this configuration, when an elastic ring is attached to prevent creep, oil is applied to a portion between the two elastic rings on the outer diameter surface of the outer ring, so that the creep preventing function is performed as described above. Enhanced.

The insulating coating is provided except for the inside of the circumferential groove, and the insulating coating covers a portion from one width surface of the outer ring to a circumferential groove of the outer ring outer diameter surface. It may be divided into two side insulating coatings and a central insulating coating that covers a portion between adjacent circumferential grooves on the outer diameter surface of the outer ring. Each of the central insulating coating and the side insulating coating is formed as a single piece and press-fitted into the outer ring. As in this configuration, the insulating coating is divided into a central insulating coating and a side insulating coating, and the central insulating coating and the side insulating coating are formed in advance. I'm done. for that reason,
The coating process of the bearing assembly line does not go off-line, continuous assembly can be performed, and an inexpensive insulating and anti-creep bearing with high productivity can be obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This rolling bearing is applied to a sealed deep groove ball bearing, and has an inner ring 1 and an outer ring 2.
Between the rolling elements 4 made of balls held in the cage 3
Is interposed. A seal mounting groove 5 is provided on the inner diameter surface of the outer ring 2.
The seal 6 is mounted in the mounting groove 5 in a press-fit state. The seal 6 is a non-contact type made of a shield plate. The tip of the seal 6 is close to a sealing groove 7 formed on the outer diameter surface of the inner ring 1 to form a labyrinth seal. In addition,
The seal 6 may be of a contact type made of an elastic body such as rubber with a cored bar or the like.

The outer ring 2 is provided with two circumferential grooves 11 on the outer diameter surface at positions near both ends, and an insulating coating 8 is provided over the width surface of the outer ring 2 and the inner surface of the circumferential groove 11. . The insulating coating 8 is made of a material having electrical insulation such as a synthetic resin or a synthetic rubber. The portion inside the circumferential groove 11 of the insulating coating 8 is formed as a groove portion 8 a that follows the inner surface shape of the circumferential groove 11. An electrically insulating elastic ring 10 such as an O-ring is detachably mounted in a circumferential groove provided with the groove portion 8a of the insulating coating 8. The elastic ring 10 has an outer diameter protruding from the insulating coating 8. The outer race 2 is also provided with a circumferential groove 17 on both side width surfaces, and the insulating coating 8 is provided with an annular ridge 8b fitted into the width surface circumferential groove 17. Further, in this example, the insulating coating 8 is made of a material having a certain degree of elasticity, is formed in a mold in advance in a shape following the outer surface shape of the outer ring 2, and is fitted and mounted on the outer ring 2 in a bearing assembling process. ing.

According to the rolling bearing of this configuration, since the outer ring 2 is covered with the insulating coating 8, the rolling element 4 and the inner ring 1 due to a potential difference between the axle box 15 and a shaft (not shown) fitted to the inner ring 1. And the outer ring 2 is prevented from being electrically eroded. The axle box 15 is made of an iron-based material. This bearing can be used as a bearing having an insulating function and an outer ring creep preventing function by using the elastic ring 10 mounted as shown in FIG. 1, or by removing the elastic ring 10 as shown in FIG. It can be used as a bearing having only an insulating function.

In the mode of use shown in FIG. 1, oil 14 such as grease is applied to a portion between the elastic rings 10 on the outer diameter surface of the insulating coating 8 and then press-fitted into the inner diameter surface of the shaft box 15. By applying the oil 14 in this manner, the oil 14 applied to the insulating coating 8 is held between the pair of elastic rings 10 and the outer diameter surface of the insulating coating and the inner diameter surface of the shaft box 15. In addition, the frictional force serving as the creeping force is reduced, and the friction of the elastic ring 10 prevents the creeping. As described above, since the creep prevention effect is enhanced by the oil 14 in the sealed state, the resistance of the outer race 2 to the axial box 15 in the axial direction is small, and the free side bearing (for example, the rear bearing B in the motor of FIG. 4) is used. Etc.). Further, since the insulating coating 8 is provided on the outer race 2 in advance, it is only necessary to apply oil when mounting the bearing on the device, and the number of assembly steps is reduced. When the creep preventing function is not required, the elastic ring 10 is removed as shown in FIG.
It can be installed vertically when mounted on

FIG. 4 shows an example of a motor using this rolling bearing. In the motor 20, among the bearings A and B supporting both ends of the motor shaft 21, the bearing A on the output end side is a fixed-side bearing that is fixedly mounted on a motor casing 22 serving as an axle box, and the other bearing B is a motor. A free side bearing that allows the casing 22 to move in the axial direction due to thermal expansion of the motor shaft 21 or the like. The rolling bearing having the configuration shown in FIG. 1 is used as the free-side bearing B. An armature 23 is mounted on the motor shaft 21 inside the motor, an output transmission component 24 such as a pulley is mounted on the output end, and a motor cooling fan 25 is mounted on the rear end.
Is installed. A field 26 is attached to the motor casing 22.

FIG. 3 shows another embodiment of the present invention. In this example, the insulating coating 8 includes two side insulating coatings 8A, 8A covering portions from one width surface of the outer ring 2 to the circumferential groove 11 of the outer ring outer diameter surface, and a circle adjacent to the outer ring outer diameter surface. Circumferential groove 11,
11 and a central insulating coating 8B that covers the portion between the two. These central insulating coating 8B and side insulating coating 8A
Are ring-shaped parts formed individually, and are attached to the outer ring 2 by press fitting. An electrically insulating elastic ring 10 such as an O-ring is fitted and attached to each circumferential groove 11. The elastic ring 10 has an outer diameter projecting from the insulating coating 8 of the outer ring 2. Note that the circumferential groove 17 on the width surface of the outer race 2 and the annular ridge 8b of the insulating coating 8 fitted into the circumferential groove 8b in the example of FIG. 1 are not provided in this embodiment. Other configurations are the same as those in the example of FIG.

When the rolling bearing is mounted on the axle box 15, the elastic ring 1 on the outer diameter surface of the insulating coating 8 is also used.
Oil 14 such as grease is applied to a portion between 0 and 10 and press-fitted into the inner diameter surface of the axle box 15. In the case of the bearing of this embodiment, the insulating coating 8 is divided into a central insulating coating 8B and a side insulating coating 8A, each of which is formed as a single piece and mounted on the outer ring 2 by press-fitting. Only needs to be added. Therefore, the coating process of the bearing assembly line does not go off-line, and continuous assembly can be performed. In this way, an insulated and anti-creep bearing that is inexpensive and has good handleability can be obtained.

[0017]

According to the rolling bearing of the present invention, a plurality of circumferential grooves are provided on the outer diameter surface of the outer ring, an insulating coating having electrical insulation is provided on the outer diameter surface of the outer ring, and the insulating groove is provided in the circumferential groove. Equipped with an electrically insulating elastic ring with an outer diameter that protrudes beyond the coating, preventing both electrolytic corrosion and creep, and also being effective as a free-side bearing that allows axial movement between the axle box and the shaft. Rolling bearing. Further, when the insulating coating is provided over the width surface of the outer race and the inner surface of the circumferential groove, and an elastic ring is detachably mounted, a portion requiring a creep preventing function and an electrolytic corrosion preventing function, A single bearing can cope with a part that requires only a single bearing without deteriorating the mountability, and can be manufactured at a lower cost than in the case of producing separate bearings. When the insulating coating is divided into a side insulating coating and a central side insulating coating, and each is formed as a single piece and press-fitted into an outer ring, productivity is increased. Furthermore, when oil is applied to the portion between the adjacent elastic rings on the outer ring outer diameter surface, the oil is retained between the insulating coating, the elastic rings on both sides, and the inner diameter surface of the axle box, and the creep force and The frictional force of the elastic ring is reduced, and an excellent anti-creep action is obtained in combination with the frictional force of the elastic ring. In this way, the oil in the sealed state enhances the creep prevention effect,
The resistance of the outer ring to the axial box in the axial direction is small, and it can be used as a free-side bearing.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a rolling bearing according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing another mounting form of the bearing to an axle box.

FIG. 3 is a partial cross-sectional view showing a mounting mode of a rolling bearing according to another embodiment of the present invention to a shaft box.

FIG. 4 is a sectional view of a motor using the bearing.

FIG. 5 is a sectional view of a conventional example.

FIG. 6 is a sectional view of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 4 ... Rolling element 8 ... Insulating coating 8A ... Side insulating coating 8B ... Central insulating coating 10 ... Elastic ring 11 ... Circular groove 14 ... Oil 15 ... Shaft box

Claims (4)

[Claims] 1. A plurality of circumferential grooves are provided on an outer diameter surface of an outer ring, and an insulating coating having electrical insulation is provided on an outer diameter surface of the outer ring,
A rolling bearing in which an electrically insulating elastic ring having an outer diameter protruding from the insulating coating is attached to the circumferential groove. 2. The electrical insulation device according to claim 1, wherein the insulating coating is provided over a width surface of the outer race and an inner surface of the circumferential groove. The rolling bearing according to claim 1, wherein the elastic ring is detachably mounted. 3. The insulating coating is provided except for the inside of the circumferential groove, and the insulating coating covers a portion from one width surface of the outer ring to a circumferential groove of the outer ring outer diameter surface. It is divided into two side insulating coatings to cover and a central insulating coating to cover the portion between adjacent circumferential grooves on the outer ring outer diameter surface, and these central insulating coatings and side insulating coatings are each formed as a single unit to form an outer ring. 2. The rolling bearing according to claim 1, which is press-fitted. 4. An oil is applied to a portion between adjacent elastic rings on an outer diameter surface of an outer ring.
The rolling bearing described.